Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
Metal oxide semiconductor (MOS) devices often require wafer acceptance tests (WATs), some of which involve heating the MOS devices using external circuitry to test their operating parameters at elevated temperature, for life-time tests. Sometimes semiconductor wafers require WATs at high temperature for reliability life time tests, for example. This requires that the WAT team operator change the WAT probe card and raise the temperature to a higher temperature in the WAT tool, which is time-consuming. Furthermore, WATs have poor wafer per hour (WPH) throughput, particularly when high temperature WATs are necessary.
Thus, what are needed in the art are improved, less time-consuming methods of performing WATs on semiconductor devices.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.